Turbine blade lacing and method of making the same



April L. F. SMALL El AL 1,953,089

TURBINE BLADE LACING AND METHOD OF MAKING THE SAME Filed May 14. 1931 2 Sheets-Sheet 1 ATTORNEY April 3, 1934. L. F. SMALL ET AL 1,953,039

TURBINE BLADE LACING AND METHOD OF MAKING THE SAME Filed May 14, 1931 2 Sheets-Sheet 2 ATTORNEY Patented Apr. 3, 1934 PATENT OFFICE TURBINE BLADE LACING AND METHOD OF MAKING THE SAME Lisle F. Small and Paul F. Lee, United States Navy, and Arvah A. Jennings, Vallejo, Calif.

Application May 14, 1931, Serial No. 537,380

4 Claims.

(Granted under the act of March 3, 1883, amended April 30, 1928; 370 0. G. 757) Our invention relates to the method of and apparatus for turbine blade lacing, and more particularly to the spacing of and rigid securement for the unsecured ends of the blades or vanes of a turbine, and it more specifically relates to the confinement of the power medium within the working areas of the blades or vanes by substantially preventing the escape thereof from the outer or free ends of the blades or vanes.

We are aware that in the prior art practice the blades or vanes have been rigidly secured, the rotor blades at their inner ends and the stator blades at their outer ends; that such blades have been laced together by being banded or wired together by a band or wire which also spaces the blades apart.

The object of our invention is to provide an improved method and apparatus whereby the unsecured ends of turbine blades are properly spaced apart and secured together in convenient groups by a lacing that also substantially confines the power medium within the working area of the blades.

A further object of our invention is to produce blade or vane spacing means and method of and apparatus for forming the same which will afford a simple, inexpensive and easily applied spacing and locking means that will also tend to prevent substantial escape of the power medium from the free ends of the blades or vanes; and to obviate the necessity of riveting or otherwise deforming each blade or vane in the attainment of such spacing and lacing.

In the accompanying drawings illustrating one embodiment of each of the aspects of our invention, Fig. 1 indicates a front elevation view, partly in section, of a plurality of turbine blades or vanes of the reaction type laced with our invention.

Fig. 1a is a top plan view thereof.

Fig. 1b is an elevation View in section on line lb-lb of Fig. 1.

Fig. 2 is a View similar to Fig. 1, but illustrating the application of our invention to the impulse type of blading.

Fig. 2a is a top plan view of the parts shown in Fig. 2.

Fig. 2b is an elevation view partly in section on line 212-212 of Fig. 2a.

Fig. 3 is an elevation view of a plurality of groups of turbine blades or vanes, each group being independently spaced apart and secured together in accordance with our invention.

Fig. 4 is a top plan view of a plurality of the turbine blades or vanes associated with the nose of our tool or apparatus for the convenient practice of our invention.

Fig. 5 is a side elevation view of the apparatus which we have devised for the convenient, dependable and economical practice of our invention.

Fig. 6 is a top plan view of a blade or vane spacing tool showing its relation to the blades or vanes.

Figs. 7 and 8 are opposite side views of such tool.

Fig. 9 is a plan view of one form of the bifurcated jaws 22 and 23 showing their relation to the blades or vanes.

Fig. 1D is a front elevation view, partly in section of a portion of a row of blades or vanes diagrammatically illustrating the spacing tool applied to a pair of the blades or vanes.

} We are aware that prior attempts have been made to attain the end accomplished by our invention by constructing each turbine blade with an integral rivet portion on its outer or unsecured end and adapted to be riveted through holes in a flat band and necessitating longer blades than required by our invention to obtain the same eliective blade or vane areas; but this practice necessitates greater manufacturing, assembly and replacement costs and tends to set up internal strains in the blades as well as the band which tend toward their crystallization and undesirable reactions due to temperature changes.

In the drawings, in which like characters of reference indicate the same parts, 10 represents, in the instance shown in Fig. 3, a portion of a turbine rotor in which the turbine blades or vanes extend radially outward therefrom. It is perfectly obvious to anyone skilled in the art that the turbine stator units each form a circle having the turbine blades or vanes secured at their outer ends thereto and extending radially inward there- 0 from, and that our invention may be similarly applied to both rotor and stator vanes or blades.

11 represents the turbine blades or vanes of the reaction type, and 12 represents such blades or vanes of the impulse type. The reaction type blades or vanes are relatively narrower than the impulse blades or vanes. Consequently a'preferably round hole is punched or drilled through each reaction type of blade near its free end, which free end is the outer end in the rotor blades or vanes and the inner end in the stator blades or vanes. Through each of these holes is passed a preferably round rod or tube 14 of a length that will pass through the desired number of blades 11, which number of blades form a group.

The blades 11 of each group are uniformly spaced apart and are then secured in such position by flattening the rod or tube 14 intermediate each blade 11. This flattening of tube 14 provides a surface 15 of substantial area between each blade 11 and in a plane substantially at right angles to the length of each blade 11 and serves the further purpose of tending to confine the greater portion of the motive fluid axially flowing through the turbine between the blades 11 and the stator or rotor and the tubes 14 and thus tends to minimize the leakage of the motive fluid at the free ends of the blades. The tubes 14 provide adequate strength as well as lightness in weight and at the same time are more readily flattened into broader surfaces 15 which serve the two-fold purpose of securing the properly spaced blades at their free ends and to reduce leakage of motive fluid at the free ends of the blades to an advantageous extent beyond that of the normal member 14.

The impulse blades 12 shown in Figs. 2, 2a and 2b, being a wider type of blade or vane, are provided each with a plurality of preferably round holes punched or drilled near the free end of each blade 12, through which holes are passed preferably round rods or tubes 14 which are flattened, as at 15 at a plurality of points between each blade 12 similar in construction and function to that described in connection with the blades 11.

It will be apparent that our invention produces a very simple turbine blade lacing which is quite durable, light in weight and cheap in proing the free end of the uniformly spaced blades,

, gage the adjacent surface of portion 21.

such securement also has some of the advantages of a shroud tending to confine the motive fluid between the blades in its axial flow.

The tube or tubes 14 may be flattened by hand tools or by any of many different apparatuses. However, there are many blades or vanes in each rotor or stator unit of a turbine, as well as many such units in each turbine, which require many flattenings of the tubes 14. To further reduce the assembly and replacement cost of turbines provided with our invention we have devised a simple, readily operable, durable and inexpensive tool for flattening the tubes 14 intermediate each blade 11 or 12. Said tool is provided with a preferably rectangular bar or body 20 having a portion 21 slidably mounted thereon. From one side of body 20 and portion 21 extend respectively jaws 22 and 23, Figs. 4 and 5, whose outer ends are curved as shown in Fig. 4 so that the juxtaposed surfaces of said jaws may occupy substantially the whole of the space between the blades 11 in the region of tube 14. Projecting from the side of portion 21 preferably opposite its jaw 23 extends a handle member 24 rigidly attached to or integral with said portion 21. A handle member 25 is provided near one end with a plurality of bearing openings 26 extending therethrough, one of which being adapted to receive a pin 27 projecting from one side of body 20 near its upper or outer end. Said pin 27 may be integral with body 20 or independent thereof and insertable into an opening therein. Adjacent the openings 26 the handle member 25 is provided with a cam surface 23 adapted to en- A spring 29 connects handle member 25 and jaw 23 so that handle members 24 and 25 are normally held apart, so that they may be moved a substantial distance toward each other when engaged by the hand, the outer portions of handle members 24 and 25 being shaped to conform to the hand grip. One of the handle members 24, 25 has a screw 30 extending therethrough provided with a lock-nut 31 and whose end is adapted to contact with the other handle member for limiting the movement of said handle members and the distance apart of the juxtaposed surfaces of the jaws 22 and 23, which distance conforms to the distance between the flattened surfaces 15 of the tube 14. This distance may be varied to any desired extent by the adjustment of screw 30.

When handle member 25 has one or the other of its bearing openings 26 occupied by pin 27 a different leverage is adapted to be exerted by its cam surface 28 upon the sliding portion 21 and its jaw 23.

From preferably opposite sides of jaw 22 extends a pin 32 adapted to serve as a gauge against the sides of blades or vanes 11 and l2'and insuring substantial uniformity in the relative positioning of jaws 22 and 23 and tube 14 between the blades 11 and 12, thus encouraging speedy manipulation of the 3 we 22, 23 and the uniform efficiency of their results.

It will be understood that the tubes 14, of a length to extend through the desired number of blades or vanes 11 and 12 are inserted into the opening of each blade in its group, with a space indicated at 35 in Fig. 3 between the ends of tubes 14, so as to admit of the expansion of the tubes 1 14 under the high working temperatures prevailing in turbine practice without any impairment. Ihe screw 30 being adjusted to afford the desired extent to which the tube 14 may be flattened, the jaws 22 and 23 are then inserted between the blades 11 and 12 to an extent determinable by the pins 32. The handle members 24 and 25 are then gripped until screw 30 limits their further movement, which correspondingly flattens the portion of tube 14 between the adjacent faces of jaws 22 and 23. This operation is repeated on the tube 14 between each blade 11 and 12. This upsets the metal of the tube 14 against each of the opposite surfaces of each blade 11 and 12 and substantially rivets the blades or vanes in their spaced positions due to the increased diameter, beyond that of each hole 14 in each such blade, and which flattened diameter also tends to act as a shroud tending to limit the escape of the motive fluid from the free ends of the blades or vanes.

The circumferential space between each of the impulse type blades 12, Figs. 2 and 2a, being greater than between the reaction type blades 11 of Figs. 1 and 1a, the tool indicated in Fig. 5 may be modified by having jaws 22 and 23 of the width between the blades of Fig. 2a which modification may be employed for flattening the hole of each tube 14 between each blade 12, but when the tool having jaws as indicated in Fig. 4 is employed several operations of such tool between each blade 12 will be required, in which case the flattening of the tube at points other than on the opposite sides of each blade 12 is in furtherance of shrouding or tending to prevent the escape of the power medium from the free ends of the blades 12.

Where the turbine blades or vanes are long, or temporary space blocks between the blades are undesirable preliminary to their being secured in blades or vanes, as indicated in Fig. 6. Preftheir spaced positions, or where such securement is desired without appreciable strain upon the blades the jaws 22 and 23 for the reaction type blades 11 are made of approximately half the width shown in Fig. 4 and such jaws bifurcated as shown in Fig. 9 to slip on opposite sides of a blade 11. Such bifurcated jaws will simultaneously flatten only that portion of tube 11 on opposite sides of the blade between the bifurcated jaws andwill not disturb the diameter of the tube juxtaposed to surfaces of adjacent blades. This will not tend to crowd successively the blade 11 away from the portion of the tube being flattened on one side only of the blade; which would place undue strains upon the blades. The bifurcated jaws 22, 23 which may be of a shape adapted thereto may also be advantageously employed in the lacing of the impulse type of blades indicated in Fig, 2a where a plurality of lacing tubes 14 are-employed to obviate a multiplicity of the strains in blade 12'liable where each tube 14 is not flattened simultaneously on opposite sides of each blade 12.

In flattening each tube 14 without rupturing or unduly distorting the metal of the tube adjacent each surface of each blade 11 and 12, the opposite sides of each jaw 22 and 23 is provided with a depression 36 adapted to be positioned upon opposite sides of the center of tube 14 to more progressively flatten such portion of the tube, substantially as indicated in Fig. 3.

Our invention also provides means for the uniform spacing of adjoining blades and holding them while they are being laced or secured in such position, as indicated in Figs. 6, '7, 8 and 10. A pair of arms 40 and 41 are pivoted at their bowed ends by pin 42 and whose opposite ends are respectively provided with curved surfaces 43 and 44 respectively adapted to fit the outer and the inner surface of each pair of turbine erably intermediate the ends of said arms 40 and 41 is a screw 45 having an angular head 46 loosely fitting opening 47 in arm 40 and pivotally secured therein by a pin 48 passing through said arm 40 and said head 46. One or more nuts 49 are threaded on screw 45 intermediate the arms 40 and 41. The free end of screw 45 is adapted to pass through a hole in the arm 41, in the instance shown in Figs. 6 and '7, and has threaded thereon a nut 50. When the surfaces 43 and 44 of respective arms 40 and 41 are the requisite distance apart the nut 49 is adjusted to contact with the inner adjacent surface of arm 41, and other nut 49, which when employed functions as a lock-nut, locks the first mentioned nut 49 in said position, which position is maintained throughout the lacing of the row of blades or vanes.

With the surfaces 43 and 44 respectively of arms 40 and 41 placed on opposite sides of a pair of blades or vanes, preferably in the relative position shown in Fig. 19, and initially on opposite sides of the ends of adjacent tubes 14, the nut 50 is tightened to clamp arm 41 firmly against its adjacent nut 49. This insures the uniform spacing of each pair of blades or vanes. The jaws 22 and 23 of the lacing tool of the unbifurcated form indicated in Fig. 4 are then placed on opposite sides of the adjacent ends of tubes 14 in a plane between said surfaces 43 and 44. Said jaws are then clamped together to fiatten the tube between them, while said arms 40 and 41 prevent the adjacent turbine blades or vanes from being spread apart as a result of the flattening of the tube between them. The spacing tool is then withdrawn and replaced on opposite sides of the next pair of blades or vanes including the adjacent one of the pair of blades or vanes previously spaced. When such succeeding pair of blades or vanes are thus properly spaced the aforesaid jaws 22 and 23 are employed to flatten the tube 14 in a plane intermediate the spacing arms 40 and 41. This operation is repeated until all the blades or vanes in each row are thus securely laced together.

In lacing the turbine blades or vanes with the bifurcated jaws 22 and 23 illustrated in Fig. 9 the spacing arms 40 and 41 are preferably initially placed on opposite sides of a pair of blades or vanes having between them the juxtaposed ends of tubes 14, as indicated in Fig. 6, and in the relative positionindicated in Fig. 10. The bifurcated'jaws" are then placed with one of the blades or vanes occupying the bifurcation, as 'in-. dicated in Fig. 9. The tube portion on opposite sides of the vane or blade and between the jaws 22 and 23, is then flattened by the bringing together of the jaws to the requisite controlled extent. This simultaneously flattens the tuhe portion on opposite surfaces of the one blade or vane occupying the bifurcation between each jaw 22 and 23. The lacing tool, including the bifurcated jaws 22 and 23, is then removed and replaced upon the adjacent blade or vane embraced by the spacing arms 40 and 41 and the tube portions 14 on adjacent faces thereof are likewise flattened. The spacing tool is then adjusted to space the adjacent pair of blades including one of the blades embraced in the previous spacing operation. The bifurcated jaws 22 and 23 are then adjusted to flatten the tube portions 14 on opposite sides of the new blade of such pair. These operations are repeated until all the blades in each row are thus securely laced.

It will be appreciated by those skilled in the art that turbine blades may be made of such metal or alloy of greater efliciency than has been heretofore possible due to our invention dispensing with the requirement that rivet portions be formed on the outer or free ends of the blades or vanes and providing that the blades may be secured together of uniform spacing without strain of the blades or vanes in either their construction, assembly or replacement, and that more rigid blades or vanes result from our invention which are freer from variations due to temperature changes.

The herein described invention may be manufactured and used by or for the Government of the United States for governmental purposes without the payment of any royalties thereon or therefor to any or all of the undersigned inventors.

Having now so fully described our invention that others skilled in the art may make and use the same therefrom, what we claim and desire to secure by Letters Patent is:

1. In a turbine blade lacing the combination with a plurality of blades or vanes comprised in an annular row each blade or vane being secured at one of its ends to a rotor or stator, each of said blades being provided with a round hole therethrough near its unsecured end, a tube having a continuous uninterrupted wall and uniform normal diameter substantially equal to that of said hole and passing through a plurality of said holes and flattened on opposite sides of each of said blades or vanes and in a direction transverse to the length of the blades or vanes, each of said flattened portions being of greater width than the diameter of said hole, a portion of the diameter of said tube adjacent one end of each of said flattened portions being in binding engagement with the wall surrounding each of its respective holes, one end of each of said flattened portions extending on opposite sides of its adjacent hole and in direct binding engagement with the adjacent surface of a blade or vane on opposite sides of the hole therethrough, and each of said blades being firmly held in position with substantially equal stress on opposite sides by direct contact therewith of the opposite ends of said flattened portions, whereby cross currents of steam are prevented through said holes and said parts may not be subjected to distortion by the stresses of the high temperature and speed changes encountered in steam turbine practice.

2. The method of securing together the metal lacing passing through a hole in the blades or vanes of steam turbines comprising simultaneously applying substantially equal force to and deforming the lacing on opposite sides of each lade or vane by simultaneously extending metal of said lacing against opposite sides of the blade or vane intermediate each pair of deformed portions of said lacing, whereby the lacing and its secured blades or vanes may not be subjected to distortion by the stress of high temperature and speed changes encountered in steam turbine practice.

3. The method of claim 2 characterized by holding the blade free from internal strains in its proper spaced relation while the lacing is being deformed on opposite sides of said held blade.

4. The method of claim 2 characterized by holding each successively secured blade free from internal strains in its proper spaced relation relative to a preceding secured blade while the lacing is being'deformed on opposite sides of said held blade.

LISLE F. SMALL. PAUL F. LEE. ARVAH A. JENNINGS. 

